Adjustable heating infusion apparatus



March 26, 1935. H, GOLDSTElN 1,995,302

ADJUSTABLE HEATING INFUSION APPARATUS Filed Nov. 24, 195s iwf A TTORNEYS.

Patented Mar. 26, 1935 ADJUSTABLE HEATING INFUSION APPARATUS HaroldGoldstein, New York, N. Y.

Application November 24, 1933, Serial No. 699,552

4 Claims.

'Ihe present invention relates to a construction for elevating andaccurately maintaining the temperature of fluids prescribed byphysicians for injection into the human system.

Many physicians are extensively using this form of therapy at thepresent time for treating human ailments. Because of the many purposesthat this form of therapy can serve, it manifestly has great practicalpossibilities. It may, for instance, be used for the intravenousinjection of fluids such as saline solutions or blood into the bloodstream via the veins. Required fluids may by it be inducted into thebody by hypodermoclysis, that is by injections through the skin. It canalso be directed to the Washing of body cavities with suitabledetergents and cleansing fluids. Likewise it comprehends the supplyingof nourishment to the body by the installation of rectal feedings. Thereis therefore little wonder that many eminent medical men are employingit more and more in their daily practice.

The widespread adoption of this form of therapy however, has beengreatly retarded by the means now in general use for regulating andcontrolling the temperature of the injected fluids. It is perfectlyapparent that unless the fluids incorporated into the body are at orsubstantially at the temperature of the body, the introduction may leadto grave injury to the patient. Thus, if the fluid is too cold there isdanger of a chill resulting from the injection. On the other hand, thepatients system is liable to overheating, and possible blood coagulationif the temperature of the fluids is immoderately high. Any benefits thatmay accrue from this mode of treatment can, therefore, only be obtainedif care is taken to adjust and retain the temperature of the fluids tothe necessary degree. The means now in vogue for controlling thetemperature of the fluids is an exceedingly crude one involving theencasing or enclosing of the fluid containing flask in hot Water bags.Due to the rate of change of temperature of the bags under atmosphericor normal conditions, one can readily perceive, that it is almost animpossibility to effect an accurate control of the temperature in thisway. For instance, due to the fall in temperature of the bags, itnecessarily follows that if the bags initially have a temperal turesufficient to provide the desired amount of heat to the fluids to beinjected, the first fraction injected will be at the optimum temperaturewhile the last will be far too cold. Chilling of the system, aspreviously pointed out, may therefore ensue. On the other hand, if thetemperature imparted by the bags to the fluid is such that the endfraction of the fluid is at the temperature required, the primaryfraction will be at aninordinately high temperature. Nothing but illeffects can result in this case. When it (Cl. 12S-254) is realized thatthese injections often last a period of twelve hours or more, one canreadily appreciate the great variance that may exist between thetemperatures of the initially and finally injected fractions of thefluid.

Attempts have been made to overcome this hazard to the utilization ofthis form of therapy by employing flasks narrower than standard tocontain the fluid, the thought back of these attempts, of course, beingto decrease the effective heat radiating and conducting surface by useof the smaller flasks. While this does permit a trifle better heatcontrol, it has the drawback that the flasks must be refilled during theprocess of injection. This, of course, increases the amount of attentionthat must be paid to the operation and in addition, increases the dangerof injecting bubbles of air with the fluid. It suffices to say that thissuggestion has not met with any great success.

It must also be remembered that these injections are seldom carried tocompletion by the medicos in charge of the injections. Generally theoperation is begun by the physician and the completion thereof left to anurse. It is, therefore, fundamental that the operation should omit anydetails which must be handled at the discretion of the nurse, for themembers of this profession are of varying degrees of intelligence andconsequently the safest course to pursue in leaving matters of primeimportance in their hands is to reduce the chance of error to a minimum.It can be appreciated from this that this particular art is in cryingneed of some simple structure which will permit of a substantiallyautomatic temperature regulation of the fluid to be inducted into thebody and which is at the same time inexpensive and practicallyfool-proof. The device according to this invention has for its objectthe attainment of these ends.

An embodiment of this device is disclosed in the accompanying drawingaccording to which:-

Fig. 1 is a front elevation of my construction.

Fig. 2 is a cross-section on line 2 2 of Fig. 1, and

Fig. 3 is a detail view of another modification of my temperaturemeasuring device.

On the drawing:

My device, as depicted in Fig. l, comprises the usual standard fluidcontaining flask 1, an injection nozzle shown on the drawing as aconventional infusion needle 2, and a tube construction indicatedgenerally at 6 for transporting the fluid from flask 1 to the infusionneedle 2 at the temperature desired for the injection.

The tube construction 6, as shown more clearly in Fig. 2, comprises aninner flexible tube 7 of rubber which serves to convey the fluid to theinfusion needle 2.

Said tube 7 is heated by means of an insulated electric resistance wire9 spirally wound about the outer surface of the tube. Current issupplied to the resistance wire by meansV of leads 14.

Injections such asare contemplated according to this invention arerarely effected by the conduction to the patient of a uniform quantity`of fluid per unit of time. On the contrary, it isV the general practiceto considerably vary the rate of flow of the fluid during the injection.Now I have found that if the fluid in questionbe heated by passing itthrough a tube heated by a resiste ance Wire uniformly wound Yabout thetube throughout its length, it is a practical impossibility to obtain asatisfactory control of the temperature. of. the fluid at the point ofinjection, throughout the operation. This is due to the fact that insuch an arrangement the initial current must b e correlated with theinitial rate of flow of the fluid so that sufficient heat is impartedtothe fluid in its progress through the tube to give the fluid at itsoutlet from the tube thetemperature desired. Now as previously eX-plained, operations of this kind are not as a general thing carried outwith the same rate of flow of. the fluid during the entire course of theoperation. Consequently as soon as the rate of ilow of; the fluid ismodied, either too little or too much heat is supplied to the. fluid. Tocompensate for thealtered rate of flow it is therefore necessary toco-ordinate the current supply with the new rate of. flow. This actionmust be taken each time the rate of flow is altered making itpractically impossible to secure any careful regulation of the finaltemperature of. the fluid.

This objection is overcome in my device by Winding the resistance wire 9about the conducting tube 7 `so that the spirals ofthe wireare moreconcentrated at the upper endthan at the lower end of the tube. Agreater amount of heat is therefore supplied to the upper endV of thetube, whichA acts toraisethe incoming fluid to substantially thetemperature required. The winding at the lower end of the tube thenfunctions to mainl tain the desired temperature or to supply the smallamount of heat required to give the desired temperature.

With tubes bearing heating coils wound in. this way, instead ofuniformly over the length of the tube, the high Vdifferential,oftemperature between the incoming fluid and theupper part of the coilAresults in a material elevation ofthe temperatureof the fluid. Thisaction obviously takes place regardless of any alteration in therate ofilow ofthe fluid. Passage of the initially heated fluid through thecooler part of the tube then results in an adjustment of the.,temperature of the fluid to that desired. There is therefore no needwith this arrangement to continuously vary the current to compensate forvariationsV in the rate of flow of the fluid.

The Vtube 7 and its. encircling resistance wire 9 is housed ina closefitting. sheathing 8 of a pliable heat insulation, such as asbestos orthe like. Due to the factA that rubber is to some extent a heatinsulator, if the coil 9 were not surrounded by a medium of high heatinsulation, the bulk of the heat'from the coil would be radiated andconducted to the outer air instead of tol the fluidV Y progressesA tothe needle 2.

ber. In order to obviate any access of a foreign medium, such as water,to the resistance wire 9, the joints between the outer tube 8c', and theinner tube 'l at the ends of tube 8dv are formed by sealing the ends ofsaid tube 8c to the inner tube. No water can therefore seep into theinterior of the tube construction 6 through the union of the inner andouter tubes during the sterilization of the tube construction 6.

The upper end of tube '7 is secured to the flask 1` through a'shortpiece of rubber tubing l5 and arconventional sight or Murphy glass 4.The rate of flow ofY the fluid from the flask 1 to the tube '7 isregulated by a pinch cock 3 of conven- Vtional construction applied tothe tubing 15.

CII

This method ofuniting the tube '7I with flask 1 is A conventional in theart. Hence the elements involved may be replaced by others of similarconstruction. V

It is of course imperative, as previously pointed out, when using adevice like the present, to. be absolutely sure that the fluid injectedby. virtue of the needle2 into a human system is at a properpredetermined temperature. In order to ascertain the temperature of thefluid as it enters the needle 2 and thereby provide a positive checkupon thetemperature of thefluid, I nd it preferable to insert betweenthe end of the tube 'Iv and the inlet of the needle 2 a temperaturemeasuring element 10c. This element comprises a metallic casing 10having an enlarged central lportion 10a defining a fluid chamber 12.Tapering connecting members 11 and 12a are formed on the ends of Vsaidcentral portion, said connecting members being provided with inlet andoutlet ports 16 and. 17. The walls of said. ports are flared toward thecentral chamber 12 to facilitate the ingress of uid to and egress of`fluid from said chamber.

The upper or top wall13a of the casing is provided with a verticaltubular element 13, thewalls of. which are extended inwardly anddownwardly through the chamber 12 to a point adjacent the bottom wall13b of said casing to form a socket 30. SaidY socket constitutes a wellfor the recepitionfof a thermometer (not shown).

It will be.apparent that with this construction the fluid entering thechamber 12 via inlet port 16. circulates about said well 30. Inasmuch.as the casing 10 is formed of a metal of very high heat conductivity,such as, aluminum, the temperature of the fluid in the chamber 12 isalmost immediately imparted to the walls ofv the thermometer well. Areading of the thermometer inthe thermometer Well 30 thus gives anaccurate indication ofthe temperature of the-fluid just prior to itspassage into the needle 2.

The. temperature measuring device just described. permits a rathercareful determination of. the temperatureVv of the fluid just. before itI nd it expedient, however, in order to render my device absolutelyfool-proof to provide, in conjunction with the temperaturemeasuring'element 10c a thermostatic'current control 5, VSaidrcurrentcontrol 5 comprises' aV heat insulated casing 20 having a which is movedinto and out of contact with element 24 in response to the heatdeveloped by the current supplied to the switch element 22 by the leads25. Said switch element 22 is, of course, included in the main circuitcarrying the current leads 14 and the resistance wire 9. The operationof the switch thereby regulates the current supplied to said resistancewire 9.

The switch is adjusted to a certain predetermined temperature by meansof a screw 26 which operates against one end of the lever 23 in such aWay that by inward movement of the screw 26 said end of the lever isdepressed while outward movement of the screw 24 permits elevation ofsaid end of the lever. The screw 26 carries a headed member 27, the baseof which is provided with an indicating marker not shown. The base ofthe headed member 27 moves over a temperature graduated disc 28. Byrotating the headed member 27 so that the marker thereon corresponds toa certain temperature on the graduated disc, the switch member 22 isadjusted to permit current fiow while the temperature does not exceedthat indicated on the disc and to break the circuit as soon as thetemperature exceeds the indicated temperature.

A careful regulation of the temperature of the fluid is made possiblewith this thermostat arrangement even though the thermostat ispositioned outside of and about the tube arrangement 6. This is due tothe housing of the thermostat in the heat insulated space defined bycasing 20. Manifestly after the device has been operating for a shorttime the temperature of said space will be substantially that of thefiuid traversing the conducting tube 7. Consequently making thethermostat responsive to the temperature of said space is in effect thesame as making the thermostat responsive to the temperature of thefluid.

Fig. 3 discloses a slightly modified form of temperature regulatingdevice 10c. The end 40 of the casing l0, adjacent the needle 2, isaccording to this modification, constructed to resemble the conventionalLuer adapter by making said end cylindrical in shape and providing itwith a slight taper. Said end 40 may then be inserted directly into thehub 41 of an ordinary Luer needle 2 and upon being rotated in said hub,may be, by virtue of the taper given thereto frictionally engaged withsaid hub. This modification does away with the adapter 31 and tubing 30of Fig. 1. The heat which is ordinarily dissipated by the passage of thefluid through said tubing and adapter is thereby conserved.

It can be appreciated that my device, though exceedingly simple inconstruction, absolutely ensures the transmission of the desired fluidto the needle 2 at the necessary temperature for the operation. Thedevice is therefore manifestly a decided improvement upon the apparatusnow employed for this purpose.

It is to be understood that while I have described a preferredmodication of my invention, I do not intend to be limited to this exactconstruction since various modifications of my device will makethemselves manifest to persons skilled in this particular art.

I claim:

1. An intravenous infusion heating tube for providing and maintaining adesired temperature of fluids to be injected into the human bodycomprising an inner fluid conducting tube of flexible material, aninsulated resistance wire spirally wound about said conducting tube, asheath of asbestos encasing said conducting tube, a protective housingof soft rubber covering said asbestos sheathing, the ends of saidprotective housing being sealed to said conducting tube, a casing of ahigh heat conducting metal having a fluid chamber, secured to the outletof said vconducting tube, a thermometer' well formed on said casing andprojecting into said fluid chamber thereof whereby the fluids enteringsaid chamber circulate about said well in intimate contact therewith.

2. A device as defined in claim l wherein the spirals of said resistancewire are more concentrated at the upper end of said conducting tube thanat the lower end thereof, whereby the spirals at the upper end of thetube serve to elevate the temperature of the fluid in the conductingtube to substantially that desired and the spirals at the lower end ofsaid tube serve to maintain said desired temperature.

3. An intravenous infusion heating tube for providing and maintaining adesired temperature of fluids to be injected into the human bodycomprising an inner flexible fluid conducting tube, an insulatedresistance wire spirally wound around said conducting tube, a fiexiblesheath of asbestos encasing said inner conducting tube and an outerprotecting tube of soft rubber housing said asbestos sheath, the ends ofsaid outer tube being sealed to said inner tube and a temperature devicecomprising a casing having an enlarged hollow central portion defining afiuid chamber and carrying at its ends connecting members for joiningsaid casing to thc conducting tube and to an infusion needle, saidconnecting members having inlet and outlet ports leading to and fromsaid fluid chamber, the top of said casing carrying a socket defining athermometer well extending through said fluid chamber, said casing beingformed of a high heat conducting metal, whereby the heat of the fluidpassing through said fluid chamber is immediately taken up by saidthermometer well.

4. An intravenous infusion heating tube for providing and maintaining adesired temperature of fluids to be injected into the human bodycomprising an inner uid conducting tube of iiexible material, aninsulated resistance Wire spirally wound about said conducting tube, thespirals of said resistance wire being more concentrated at the upper endof said conducting tube than at the lower end thereof, a sheath ofasbestos encasing said conducting tube, a protective housing of softrubber covering said asbestos sheathing, the ends of said protectivehousing being sealed to said conducting tube, a casing of a high heatconducting metal secured to the outlet of said conducting tube, anenlargement in said casing to hold a temperature measuring device, meansmounted on said conducting tube for visually indicating the temperaturedesired and means for automatically controlling the desired temperatureof the fluid in the tube.

HAROLD GOLDSTEIN.

